Every professional LVP installation over concrete (basements, slab-on-grade rooms) starts with a moisture test — either a calcium chloride test or an in-situ RH probe. This isn’t optional. It’s the single most predictive check for whether the floor will fail early.

If your installer’s quote or verbal explanation doesn’t include moisture testing, ask directly. “We don’t do that here” or “Vapor barrier handles it” are wrong answers. The vapor barrier’s job is to manage moisture that testing has identified — not substitute for the test itself.

Every quote should specify wear layer thickness in mils. “12-mil,” “20-mil,” or “28-mil” — those are the numbers you’re looking for. If the quote just says “LVP” or “waterproof vinyl,” you don’t know what you’re buying.

Ask specifically: “What’s the wear layer thickness in mils on the product you’re quoting?” The answer should come immediately. If it doesn’t, the installer either doesn’t know or doesn’t want you to know. Both are bad signs.

LVP installations require the subfloor to be within 3/16″ of flat over any 10-foot radius. Older Sioux Falls homes (especially 1960s-1980s builds) often have subfloors that don’t meet this — dips near center-load walls, high spots at seam joints, minor slopes toward drains.

Quality installers check this with a 10-foot straight edge before installing. They’ll level as needed with self-leveling compound. Cheap installations skip this check entirely, install directly over the uneven surface, and the LVP joints separate within 2-4 years as the floor flexes under normal use.

Basements and slab-on-grade installations need a vapor barrier under the LVP. Some LVP products include integrated pad-plus-vapor-barrier; others require supplemental barrier. Any installer working on your basement should know which their specific product requires.

“You don’t need one” isn’t an acceptable answer for a below-grade installation. The moisture might not be visible today. It shows up as delaminated planks and mildew smell in year three.

Standard practice for residential LVP installations in Sioux Falls: 25-50% deposit at signing, balance on completion. Occasionally a small material-order deposit on top of that. Anything above 50% before work starts is a red flag.

Full payment upfront is nearly universal among storm-chaser and door-to-door operators who disappear after cashing the check. It’s rare among established local contractors. If you’re being pressured for full payment before installation, walk away.

Every LVP installation should carry two warranties: manufacturer material warranty (typically 15-25 years residential) and installer workmanship warranty (typically 1-5 years). Both should be delivered in writing at project completion.

Verbal warranties are worth nothing when the installer is unreachable. “We stand behind our work” is not a warranty. A written document specifying what’s covered, for how long, and what your remedy is — that’s a warranty.

LVP planks should acclimate to your home’s temperature and humidity for at least 48 hours before installation. Some products require 72 hours. Skipping this step causes gaps or buckling as the planks adjust to your climate after installation.

Ask when the material will arrive at your home relative to installation. Same-day delivery-and-install is a red flag for anything except commercial installations in climate-controlled buildings.

Every LVP installation needs a 1/4″ to 3/8″ expansion gap around the perimeter of the room — hidden by baseboards or quarter-round. This gap lets the floor expand and contract with temperature.

Watch how the installer describes the finish. If they mention pushing planks tight against walls or skipping trim removal, they may be skipping the expansion gap. Result: buckled floor within 12-18 months of the first big temperature swing.

Every contractor working in your home should carry general liability insurance and workers’ comp. Legitimate installers can produce a Certificate of Insurance (COI) on request within 24-48 hours.

Uninsured contractors are one lawsuit away from bankruptcy — and if a worker is injured on your property while uninsured, you may become the deep pocket. This applies to LVP installers as much as roofers or windows contractors.

Established Sioux Falls installers should be able to provide 3-5 recent local references — homeowners in the area whose installations you can drive by, or who will answer a phone call about their experience.

If references are only from years ago, or only from other markets, that’s a red flag for a new operator, a struggling business, or someone who just showed up after the last hail season. Local flooring is a relationship business — good installers build books of local clients quickly.